Novak Djokovic has ominously warned that he will be at full strength both mentally and physically when he plays in Sunday's Wimbledon final - despite his five-set marathon victory over Juan Martin del Potro.

Top seed and US Open champion Juan Martin Del Potro was dumped out of the Rakuten Japan Open in Tokyo on Tuesday as he lost his first-round match 6-4 6-4 against French qualifier Edouard Roger-Vasselin.